1. Technical Field
The field of art to which this invention pertains may be generally located in the classes of devices relating to gripping devices and steady rests.
2. Background Information
It is known in the machine tool art to employ steady rests for rotatably supporting elongated cylindrical workpieces for abrading and turning operations. It is also known in the robot gripper art to provide gripping devices for moving workpieces between selected positions. However, a disadvantage of such prior art steady rests and gripping devices is that they are limited in their uses, and they are not adapted to carry out both an automatic centering and a workpiece gripping operation.
A disadvantage of the prior art steady rest and gripping devices is that their workpiece engaging members are movable only along one axis, which limits their ability to perform various centering and workpiece gripping operations. A disadvantage of some of the prior art gripping devices is that, although it is advertised that they provide a parallel motion, the gripper arms for such gripping devices move in an arc. Accordingly, if the gripper arms have a V-shaped gripping jaw or finger, then it is necessary to reprogram the controls for the gripping device for each size workpiece, since with different diameters, the V-shaped jaws will be at different positions along the arcuate path through which the gripper jaws are moved, making it necessary to reprogram the gripping device for different diameter workpieces. There are some true parallel motion grippers on the market, but a disadvantage of the last mentioned grippers is that they basically work off a wedge means, which provides only a very short stroke or movement on one axis for their gripping arms. A disadvantage of the last mentioned true parallel grippers is that they cannot be used for a wide range of different diameter workpieces, and accordingly, they lack versatility. It is also known in the prior art to provide a true centering steady rest, having a center wear pad and two side wear pads for movement along only one axis and into supporting engagement with a workpiece, as shown in U.S. Pat. No. 4,399,639.